Shiho Sato1, Masaki Iwasaki2, Hiroyoshi Suzuki3, Shunji Mugikura4, Kazutaka Jin5, Teiji Tominaga6, Kei Takase7, Shoki Takahashi8, Nobukazu Nakasato9. 1. Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: Shihosato0809@gmail.com. 2. Department of Neurosurgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: iwa@nsg.med.tohoku.ac.jp. 3. Department of Diagnostic Pathology, Sendai Medical Center, 2-8-8 Miyagino, Miyagino-ku, Sendai 983-8520, Japan. Electronic address: hirosuzsnh@gmail.com. 4. Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: mugi844@gmail.com. 5. Department of Epileptology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: jinkazu2007@gmail.com. 6. Department of Neurosurgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: tomi@nsg.med.tohoku.ac.jp. 7. Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: ktakase@rad.med.tohoku.ac.jp. 8. Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: t-shoki@rad.med.tohoku.ac.jp. 9. Department of Epileptology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: nkst@med.tohoku.ac.jp.
Abstract
OBJECT: The use of T2 relaxometry was investigated to detect non-sclerotic epileptogenic abnormality of the hippocampus in presurgical evaluation of temporal lobe epilepsy (TLE). METHODS: This prospective study included 30 patients who underwent hippocampectomy as part of surgical treatment of refractory TLE. Ten patients had structural epileptogenic lesions in the extra-hippocampal temporal lobe. Twelve patients underwent intracranial electroencephalography (iEEG) study before surgery. Visual assessment of atrophy and increased T2 signal intensity, volumetry, and T2 relaxometry of hippocampus were performed pre-operatively using 3T magnetic resonance imaging, and compared with the neuropathological findings and iEEG findings. Magnetic resonance imaging of 30 age- and sex-matched healthy controls was used to establish normal values, which were defined as z score within 2. RESULTS: Visual assessment, volumetry, and T2 relaxometry detected hippocampal abnormalities on the surgical side in 16 (53%), 16 (53%), and 26 (87%) patients, respectively. Hippocampal volume loss was always associated with prolonged T2 relaxation time, and supported by histopathological diagnosis of HS in all cases except one. Hippocampal abnormality was detected only by T2 relaxometry in nine patients (30%). Pathological diagnosis of these cases included mild HS in one, microdysgenesis in one, and granule cell pathology in three. Four patients with normal hippocampal volume and T2 relaxation time had no HS or granule cell pathology. Prolonged T2 relaxation time was associated with medial temporal seizure onset in iEEG (p<0.05). CONCLUSIONS: T2 relaxometry improves the detection of non-sclerotic epileptogenic abnormality of the hippocampus.
OBJECT: The use of T2 relaxometry was investigated to detect non-sclerotic epileptogenic abnormality of the hippocampus in presurgical evaluation of temporal lobe epilepsy (TLE). METHODS: This prospective study included 30 patients who underwent hippocampectomy as part of surgical treatment of refractory TLE. Ten patients had structural epileptogenic lesions in the extra-hippocampal temporal lobe. Twelve patients underwent intracranial electroencephalography (iEEG) study before surgery. Visual assessment of atrophy and increased T2 signal intensity, volumetry, and T2 relaxometry of hippocampus were performed pre-operatively using 3T magnetic resonance imaging, and compared with the neuropathological findings and iEEG findings. Magnetic resonance imaging of 30 age- and sex-matched healthy controls was used to establish normal values, which were defined as z score within 2. RESULTS: Visual assessment, volumetry, and T2 relaxometry detected hippocampal abnormalities on the surgical side in 16 (53%), 16 (53%), and 26 (87%) patients, respectively. Hippocampal volume loss was always associated with prolonged T2 relaxation time, and supported by histopathological diagnosis of HS in all cases except one. Hippocampal abnormality was detected only by T2 relaxometry in nine patients (30%). Pathological diagnosis of these cases included mild HS in one, microdysgenesis in one, and granule cell pathology in three. Four patients with normal hippocampal volume and T2 relaxation time had no HS or granule cell pathology. Prolonged T2 relaxation time was associated with medial temporal seizure onset in iEEG (p<0.05). CONCLUSIONS: T2 relaxometry improves the detection of non-sclerotic epileptogenic abnormality of the hippocampus.
Authors: Gavin P Winston; Sjoerd B Vos; Jane L Burdett; M Jorge Cardoso; Sebastien Ourselin; John S Duncan Journal: Epilepsia Date: 2017-07-12 Impact factor: 5.864